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Battery Size Codes

The battery size code can contain not only information about the physical size of the battery, but can also indicate the type and location of the battery terminals as well as the vent location for conventional batteries. There are three basic types of battery codes, two for conventional batteries and one for maintenance free (MF) batteries.

Conventional Batteries

Numeric Codes

Nominal Voltage

As an example of a numeric code, a common conventional battery size is 12N14-3A. The first number indicates the nominal voltage of the battery, which can be either a 6 for older 6 volt systems or 12 (as in the example) which indicates it is a 12 volt battery.

Amp/hour Capacity

The letter “N” is simply a spacing digit to separate the nominal voltage from the next number (14 in the example) which indicates the amp/hour capacity of the battery. The amp/hour capacity is determined by the physical size of the battery, the larger the battery is the larger its amp/hour capacity. In this case, the 14 indicates that a fully charged battery of this size will light a bulb that uses exactly one ampere for 14 hours until it is considered dead (an actual voltage reading of 10.5 volts is considered a dead 12 volt battery, 5.25 volts for a 6 volt battery).

Terminal Location

The 3 indicates the location of the battery terminals when viewed from above and could be a 1, 2, 3 or 4.

_
                   +

1

                   _
+

2

_                 +

3

+                 _

4

Vent Opening Location

The letter “A” indicates the location of the vent opening when viewed from above and could be an A, B, C or D. Vent location A is on the left end, B is on the right end, C is in the front and D is in the rear.

Alpha-numeric Codes

Nominal Voltage

As an example of an alpha-numeric code, another common conventional battery size is YB14L-A2. The first two letters indicate the battery manufacturer, in this case Yuasa Battery (if it was manufactured by Bikemaster, the letters would be BB). The nominal voltage of all batteries using the alpha-numeric code is 12 volts.

Amp/hour Capacity

The first number (14 in the example) indicates the amp/hour capacity of the battery. The amp/hour capacity is determined by the physical size of the battery, the larger the battery is the larger its amp/hour capacity. In this case, the 14 indicates that a fully charged battery of this size will light a bulb that uses exactly one ampere for 14 hours until it is considered dead (an actual voltage reading of 10.5 volts is considered a dead 12 volt battery).

Terminal Location

The L indicates the location of the battery terminals when viewed from above and could be an A, B or L.

_                 +

L

+                 _

A or B

Vent Opening Location

The letter “A” after the “-” indicates the location of the vent opening when viewed from above and could be an A, B, C or D. Vent location A is on the left end, B is on the right end, C is in the front and D is in the rear.

Terminal Type

The last number (2 in the example) indicates the type of battery terminal used. 1 indicates battery terminals with the battery bolts going in from the side, 2 indicates terminals with the battery bolts going in from the top.

Maintenance Free (MF) Batteries

Nominal Voltage

As an example of a maintenance free battery code, a common MF battery size is YTX12A-BS. The first letter indicates the manufacturer of the MF battery (in this case Yuasa) plus the letters TX (if it was manufactured by Bikemaster, the letters would be BTX). The nominal voltage of all MF batteries is 12 volts.

Amp/hour Capacity

The number (12 in the example) indicates the amp/hour capacity of the battery. The amp/hour capacity is determined by the physical size of the battery, the larger the battery is the larger its amp/hour capacity. In this case, the 12 indicates that a fully charged battery of this size will light a bulb that uses exactly one ampere for 12 hours until it is considered dead (an actual voltage reading of 10.5 volts is considered a dead 12 volt battery).

Terminal Location

The A indicates the location of the battery terminals when viewed from above and could be an A or L.

_                 +

L

+                 _

A

Terminal Type

The letter “B” indicates the type of terminal, which is always going to be terminals with the battery bolts going in from the top.

Battery Type

The final letter “S” indicates that it is a “sealed” maintenance free battery.

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